An overview of the extant genera and subgenera of the order Scolopendromorpha (Chilopoda): a new identification key and updated diagnoses
Author
Schileyko, Arkady A.
schileyko1965@gmail.com
Author
Vahtera, Varpu
varpu.vahtera@gmail.com
Author
Edgecombe, Gregory D.
0000-0002-9591-8011
schileyko1965@gmail.com
text
Zootaxa
2020
2020-08-10
4825
1
1
64
journal article
8703
10.11646/zootaxa.4825.1.1
5ab5f5c8-481e-4d1a-8643-21e72c367278
1175-5326
4402145
F230F199-1C94-4E2E-9CE4-5F56212C015F
(!)
Digitipes
Attems, 1930
Figs 89–92
Type
species.
Digitipes verdascens
Attems, 1930
(by monotypy).
Diagnosis.
Median tooth of labrum very small, much shorter than lateral labral lobes (
Fig. 90
). Forcipular toothplates present, trochantero-prefemur with well-developed process (
Fig. 91
). Rarely some posterior tergites with well-developed longitudinal keels (for example in
D. barnabasi
Jangi and Dass, 1984
; see fig. 10 of
Joshi & Edgecombe 2013
), usually these keels lacking or very poorly developed. Sternites may bear paramedian sutures (or sulci) as well as a median longitudinal sulcus and posterior depression (
Fig. 92
). LBS 7 lacking spiracles, the latter with atrium. Legs with tarsal spur(s), the only exception—
D. nudus
(Pocock, 1890)
(former
D. periyarensis
Joshi & Edgecombe, 2013
) (see below). Coxopleural process from short to moderately long, with apical spines. Ultimate prefemur with spines but lacking corner spine, pretarsus well-developed. Femur of males with well-developed (but incomplete) medial longitudinal depression leading to an obtuse conical distomedial process (
Fig. 89
) that bears scattered setae (see also figs 9, 21,
42, 54 in
Siriwut
et al
. 2015
).
Number of species.
9 (
Edgecombe & Bonato 2011: 402
), 11 (
Bonato
et al
. 2016
), 10 (
Siriwut
et al.
2015: 76
).
Sexual dimorphism.
Present.
Remarks.
Treated as a genus in
Edgecombe & Bonato (2011: 402)
,
Joshi & Edgecombe (2013: 99)
,
Vahtera
et al
. (2013: 594)
,
Joshi & Edgecombe (2018: 1318)
,
Joshi & Edgecombe (2019: 3)
.
Siriwut
et al.
(2015)
considered it as a genus but wrote (p. 83): “Within the
Otostigminae
, members of
Digitipes
were separated into two clades”.
Joshi & Edgecombe (2017)
analyzed in detail the Indian species of this genus. More densely sampled molecular phylogenies by
Siriwut
et al.
(2018)
and
Joshi
et al
. (2020)
depicted
Digitipes
as monophyletic apart from the nesting of
Otostigmus nudus
Pocock, 1890
(former
D. periyarensis
) within it. However, more material should be studied (using both traditional and molecular approaches) to be sure to which genus (
Otistigmus
or
Digitipes
) this species belongs.
An incomplete (it lacks some posterior LBS) specimen of
Digitipes
sp. (Rc 7565 from E
Gabon
) has a very small median tooth of the labrum (
Fig. 90
), which is also characteristic within
Otostigminae
for
Sterropristes
+
Edentistoma
(see below), and an unusually wide process of the forcipular trochantero-prefemur (
Fig. 91
). In addition, this specimen has no legs with tarsal spurs (a very rare condition in
Otostigminae
), so it is similar to the former
Digitipes periyarensis
in this (and some other) morphological aspects.
An obtuse conical distomedial process of the femur of male
Digitipes
is (with the exception of being spineless) similar to the standard corner spine of the ultimate prefemur of
Scolopendridae
.
We consider this genus as problematic since the femoral characters are restricted to mature males such that the females of
Digitipes
cannot be morphologically separated from those of
Otostigmus
(
Otostigmus
)
. In addition, “Specimens that possess the femoral process make up a small percentage of our total sample of
Digitipes
” (
Joshi & Edgecombe 2013: 101
). Analyzing the monophyly of
Digitipes
Vahtera
et al
. (2013: 595)
wrote: “… the clade is sensitive to parameter set variation as it is resolved as monophyletic only under two of the six explored parameter sets”, although the data of Siriwut
at al
. (2018) and
Joshi
et al
. (2020)
strengthened the case for monophyly using more species.
All diagnostic features of
Digitipes
listed by
Joshi & Edgecombe (2013:100)
except for the male’s longitudinal groove and distomedial process of the ultimate femur are shared by all representatives of the nominotypical subgenus of
Otostigmus
. The “composite description” of
Digitipes
provided by Siriwut
at al
. (2015: 75) also perfectly fits for
Otostigmus
(
Otostigmus
)
, apart from the aforementioned male characters. Taking into consideration the virtual morphological identity of these two genera, and the fact that the monophyly of
Digitipes
is not well supported by the morphological data, we consider this genus to require further investigation.